Generally a hearing aid system according to the invention is understood as meaning any system which provides an output signal that can be perceived as an acoustic signal by a user or contributes to providing such an output signal, and which has means which are used to compensate for an individual hearing deficiency of the user or contribute to compensating for the hearing deficiency of the user. These systems may comprise hearing aids which can be worn on the body or on the head, in particular on or in the ear, and can be fully or partially implanted. However, some devices whose main aim is not to compensate for a hearing deficiency may also be regarded as hearing aid systems, for example consumer electronic devices (televisions, hi-fi systems, mobile phones, MP3 players etc.), provided they have, however, measures for compensating for an individual hearing deficiency.
Within the present context a hearing aid may be understood as a small, battery-powered, microelectronic device designed to be worn behind or in the human ear by a hearing-impaired user.
Prior to use, the hearing aid is adjusted by a hearing aid fitter according to a prescription. The prescription is conventionally based on a hearing test that measures the hearing threshold, resulting in a so-called audiogram, of the performance of the hearing-impaired user's unaided hearing. The prescription may be developed to reach a setting where the hearing aid will alleviate a hearing deficiency by amplifying sound at frequencies in those parts of the audible frequency range where the user suffers a hearing deficit in the form of an elevated hearing threshold.
A hearing aid comprises one or more microphones, a battery, a microelectronic circuit comprising a signal processor, and an acoustic output transducer. The signal processor is preferably a digital signal processor. The hearing aid is enclosed in a casing suitable for fitting behind or in a human ear. For this type of traditional hearing aids the mechanical design has developed into a number of general categories. As the name suggests, Behind-The-Ear (BTE) hearing aids are worn behind the ear. To be more precise, an electronics unit comprising a housing containing the major electronics parts thereof is worn behind the ear and an earpiece for emitting sound to the hearing aid user is worn in the ear, e.g. in the concha or the ear canal. In a traditional BTE hearing aid, a sound tube is used to convey sound from the output transducer, which in hearing aid terminology is normally referred to as the receiver, located in the housing of the electronics unit and to the ear canal. In some modern types of hearing aids a conducting member comprising electrical conductors conveys an electric signal from the housing and to a receiver placed in the earpiece in the ear. Such hearing aids are commonly referred to as Receiver-In-The-Ear (RITE) hearing aids. In a specific type of RITE hearing aids the receiver is placed inside the ear canal. This category is sometimes referred to as Receiver-In-Canal (RIC) hearing aids. In-The-Ear (ITE) hearing aids are designed for arrangement in the ear, normally in the funnel-shaped outer part of the ear canal. In a specific type of ITE hearing aids the hearing aid is placed substantially inside the ear canal. This category is sometimes referred to as Completely-In-Canal (CIC) hearing aids. This type of hearing aid requires an especially compact design in order to allow it to be arranged in the ear canal, while accommodating the components necessary for operation of the hearing aid.
Some hearing aid systems do not comprise a traditional loudspeaker as output transducer. Examples of hearing aid systems that do not comprise a traditional loudspeaker are cochlear implants, implantable middle ear hearing devices (IMEHD) and bone-anchored hearing aids (BAHA).Within the present context a hearing aid system may comprise a single hearing aid (a so called monaural hearing aid system) or comprise two hearing aids, one for each ear of the hearing aid user (a so called binaural hearing aid system). Furthermore the hearing aid system may comprise an external device, such as a smart phone having software applications adapted to interact with other devices of the hearing aid system, or the external device alone may function as a hearing aid system. Thus within the present context the term “hearing aid system device” may denote a traditional hearing aid or an external device.
It is well known for persons skilled in the art of hearing aid systems that some hearing aid system users are not satisfied with results of conventional hearing-aid fitting that primarily is based on measuring an elevated hearing threshold.
A subgroup of potential hearing aid users is assumed to suffer from an auditory neuro-synaptopathy due to aging or ototoxic drug exposure or noise trauma. This type of hearing deficit may also be denoted an auditory neurodegeneration if preferring a more general term. Auditory neuro-synaptopathy is a dysfunction in the synapses that transmits hearing information from e.g. the inner hair cells of the cochlea and to nerve-fibres that carry the hearing information further on to the processing parts of the brain. A plurality of synapses are required to be activated in order to provide that a nerve-fibre is activated and transmits the hearing information.
Measurement of the hearing threshold cannot generally be used to diagnose this type of hearing deficiency. Many hearing aid fitters may therefore be hesitant to suggest or apply potentially beneficial sound-processing features specifically adapted to relieve an auditory neuro-synaptopathy, unless a hearing aid fitting system capable of detecting an auditory neuro-synaptopathy is available.
It is therefore a feature of the present invention to provide a hearing aid fitting system or some other computerized device capable of detecting an auditory neuro-synaptopathy.
Such a measurement may also detect hearing deficiencies for those persons that complain about a problem with understanding speech in noise, but do not reveal an elevated hearing threshold (that may also be denoted reduced pure-tone sensitivity). Today, these persons are not prescribed hearing-aid system treatment and are therefore left to cope with their hearing deficit.
According to another aspect it is a feature of the present invention to suggest a method of fitting a hearing aid system that comprises detection of an auditory neuro-synaptopathy in a manner that is time-efficient and easy to execute such that it may be suitable for implementation as part of a standard hearing aid fitting procedure.
It is another feature of the present invention to provide a hearing aid fitting system capable of suggesting and providing features specifically directed at relieving an auditory neuro-synaptopathy.